Recently I purchased a used 98 cabrio with around 109,000 miles, that at the time was running fine until it started to run hot at about 230 as indicated by the temp gauge. So I replaced the thermostat and the coolant fan control thermal switch. After that it seemed to be fixed the car ran at around 200 to 210. A week later it started to run hot again around 230. After checking the car again I found that the cooling fan was on only when the A/C is on. After testing the coolant fan control module it was bad so I replaced it. After replacing it the car still runs at 230, and when I looked under the hood after driving it the fan shut off as soon as I got the hood up. So the fan was on at some point without the A/C being on. The next thing I'm going to replace is the water pump could there be anything else that would cause it to run hot?

 

Have you tried doing a coolant flush?

What makes a car run hot

It sounds like you may be in need of a new radiator.